Main.java

import java.util.Scanner;
import java.util.Arrays;

public class Main {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);

        int N = in.nextInt();

        int[][] arr = new int[N][2];

        for(int i = 0; i < N; i++){
            arr[i][0] = in.nextInt();
            arr[i][1] = in.nextInt();
        }

        Arrays.sort(arr, (e1, e2) -> {
            if(e1[0] == e2[0]){
                return Integer.compare(e1[1], e2[1]);
            } else {
                return Integer.compare(e1[0], e2[0]);
            }
        });

        for(int i=0; i < N; i++){
            System.out.println(arr[i][0] + " " + arr[i][1]);
        }

        in.close();
    }
}